how to get the oracle parameter MAXINSTANCES on openvms 8.3

[Song_Charles]

hi,

the ORACLE is now upgraded to RAC/9i2(9.2.0.8),and OpenVMS V8.3 was with ECOs(VMS83A_ACRTL V5.0, VMS83A_FIBRE_SCSI V6.0, VMS83A_RMS V9.0, VMS83A_SYS V8.0, VMS83A_UPDATE V8.0, VMS83A_PCSI V2.0).

For 5 nodes(ES40) in cluster will be join RAC, I must know the oracle's MAXINSTANCES parameter,but from the oracle database control files(trace to ASCII format), I couldn't find it, how can I get the MAXINSTANCES parameter?

I used the oracle tools DBCA to creat the database, and there was no item to assign the MAXINSTANCES parameter.

Thanks
Charles Song

[Duncan Morris · Accepted solution]

Charles,

In order to determine the existing value of MAXINSTANCES, run the following query:

select type,records_total
from v$controlfile_record_section
where type='REDO THREAD';

OUTPUT:
TYPE RECORDS_TOTAL
----------------- -------------
REDO THREAD 4

If the value for RECORDS_TOTAL for the REDO THREAD type is greater than or equal to the desired number of RAC instances, then you can skip step 5. Otherwise, follow the instructions in Step 5 in order to increase the value of MAXINSTANCES. In the example output provided above, MAXINSTANCES is set to 4.

Duncan

[Song_Charles]

Duncan,

the output was: 63

SQL> select type,records_total from v$controlfile_record_section
2 where type='REDO THREAD';

TYPE RECORDS_TOTAL
-------------------- -------------
REDO THREAD 63

SQL>

Is it means the MAXINSTANCES 63?
THE DEFAULT volume?
and when I configurating the multi-node RAC(5 nodes), what should be focus?

Thanks
Charles Song

[Hein van den Heuvel]

>> For 5 nodes(ES40) in cluster will be join RAC, I must know the oracle's MAXINSTANCES parameter,but from the oracle database control files(trace to ASCII format), I couldn't find it, how can I get the MAXINSTANCES parameter?


Just set it to a value you like?

You are almost there... "ALTER DATABASE BACKUP CONTROLFILE TO TRACE"...
Re-create control files.

many hints as you google for 'cloning databases'

google: +maxinstances +default +openvms +site:oracle.com


http://download.oracle.com/docs/html/A90868_01/ch1_admi.htm
9i-1: ... MAXINSTANCES default = 16, max = 63"


http://download.oracle.com/docs/cd/B19306_01/install.102/b25414.pdf
10.2 - Installation guide

"The default MAXINSTANCES value is 32 (recommended)"
That's for 10g... where you should be?


http://download.oracle.com/docs/cd/B19306_01/server.102/b25416.pdf
Admin Ref - A.1 indicates: "CREATE CONTROLFILE and CREATE DATABASE Parameters ... MAXINSTANCES default = 1, max = 63"



>> when I configurating the multi-node RAC(5 nodes), what should be focus?

To have MAXINSTANCES larger than 5 and any possible number you for see in the near future. 8? 10 ? 16?


>> it means the MAXINSTANCES 63?

That would be the max

You may also want to query SELECT * FROM V$ACTIVE_INSTANCES


http://asktom.oracle.com/pls/asktom/f?p=100:11:3026321194124574::::P11_QUESTION_ID:318216852435

hth,
Hein.